air/fuel ratio gauge

#1 07-01-2003, 08:53 PM

Since there is two oxigen sensors, how would you connect the air/fuel ratio gauge? Can anybody help? PS I would appreciate you guys input.

AFBeefcake · #2 07-01-2003, 10:25 PM

I wired mine in to O2 #2 which is pin 6 white wire on the 22 pin connector on the ECU.

hope that helps you out.

svx_commuter · #3 07-02-2003, 05:03 AM

What is the purpose of this air/fuel ratio gauge?

svxfiles · #4 07-02-2003, 07:52 AM

for most people, it is an instrument to moniter the ratio of air to fuel, so that they can moniter and correct if necessary, any major modifications can alter the a/f so its a good idea, but for me its a pretty blinky thingy. i like bling-bling. ps, wired it strait into the right o2 sensor pigtail

#5 07-02-2003, 09:12 AM

I'm a little mechanically inclined but problably not like you are. Can you be more specific, what do you mean with pigtail?

svx_commuter · #6 07-02-2003, 09:49 AM

svxfiles, Do you have a picture of this a/f monitor? This would be a good thing to have if one runs NOS?

AFBeefcake · #7 07-02-2003, 01:15 PM

here is a pic of mine
http://www.subaru-svx.net/photos/fil...fcake/6052.JPG

svxfiles · #8 07-02-2003, 03:58 PM

the one i used was a NORDSKOG part #nrd-m7009 from summit at $35.95 and i was able to mount this round guage in the square hole that normally has the change holder to the right of the steering column and left of the radio knob. from 94 on that is the ob2 plug. it is very important to know that your car is not too lean!! that can burn valves, melt pistons and just cook your engine. if its too rich you get bad gas milage have less power, and possably dilute the engine oil enough to spin a bearing. the pigtail is the end of a wire or wiring loom. when i hooked mine up i chose the right side because it was easier to reach. with NOX things can super heat super fast, so an a/f guage can be a great tuning guide.an exhaust temp guage would olso be a great tuning guide because a spike in temp would indicate a lean condition. without any modifications this is not really necessary, but they give information that might save your engine
ps the techs at nordskog are very helpful if you have a question or problem

Red Wolf · #9 07-02-2003, 07:23 PM

One other thing you might want to consider about an air/fuel ratio gauge is that the vast majority of cars use what are known as narrow band o2 sensors, which can only tell if the ratio is off by a relatively small amount.

On modern cars with closed loop computer systems, all you will see under normal operation is the meter bouncing from one end of the scale to the other and back. Under wide open throttle, most cars go into open loop mode, and the a/f ratio will become a fixed value.

A wide-band o2 sensor is a serious tuning tool, with a serious pricetag to go with it. The sensor alone retails for around $600. The advantage is that a wide band will show exactly what the a/f ratio is, instead of just indicating if its high or low.

YMMV, as I learned this from the Toyota Supra and Mitsubishi Eclipse communities and I don't know how this applies to the SVX.

John

Chicane · #10 07-02-2003, 07:55 PM

Rice rice baby..do doo dodododod da.

Seriously, people want them because they see them on race cars. Same with big rims. And spoilers. And sponsor stickers. People want race cars, so they just make their cars 'look' like race cars. Personally I'm a fan of a car that DOESNT look like a racecar but actually performs like one. :|

- Rob

mbtoloczko · #11 07-03-2003, 12:22 AM

Quote:

Originally posted by Red Wolf
One other thing you might want to consider about an air/fuel ratio gauge is that the vast majority of cars use what are known as narrow band o2 sensors, which can only tell if the ratio is off by a relatively small amount.

On modern cars with closed loop computer systems, all you will see under normal operation is the meter bouncing from one end of the scale to the other and back. Under wide open throttle, most cars go into open loop mode, and the a/f ratio will become a fixed value.

A wide-band o2 sensor is a serious tuning tool, with a serious pricetag to go with it. The sensor alone retails for around $600. The advantage is that a wide band will show exactly what the a/f ratio is, instead of just indicating if its high or low.

YMMV, as I learned this from the Toyota Supra and Mitsubishi Eclipse communities and I don't know how this applies to the SVX.

John

So, are there O2 sensor gauges that are calibrated to a narrow band O2 sensor, so that when the gauge actually goes into the "lean" range, the a/f mixture is truly lean? Or does "lean" simply mean something somewhat less than stoic without being able to say that its within a range of actual values?

svxfiles · #12 07-03-2003, 10:00 AM

yes, the narrow band o2 sensors are what our cars are equipped with from the factory. and yes, my guage bounces up and down from full lean to the middle of the guage all the time, showing me that the o2 is doing its thing. however during the first few minutes of running,(when the engine is cold ) and most importantly at wide open throttle it shows wheather im too rich or too lean.with that info i can adjust my fuel pressure to keep the wot a/f at about 14 to 1, or the middle of the guage.
the o2 sensor constantly adjusts this but not at wot, that is a fixed but adjustable value

lee · #13 07-06-2003, 07:11 AM

Correct me where I'm wrong (please), but I always thought A/F gauges were for turbo cars - so that if was running lean at WOT you knew to back off before destroying the engine.

If it's just because you like to watch gauges or think they're neat, then OK; but, if there's another reason I would like to know - thanks.

svxfiles · #14 07-07-2003, 03:52 PM

lee, it would be good for any modified engine. when you increase the volume of air thru an aftermarket air filter.or a custom intake tube, or remove the cats, or change the fuel pressure, or vary the cam timing, or add nox or evan a big ram-air scoop, all of this can create a lean condition. if lean enough, it will burn up the exhaust valves, or possably melt the pistons. if it is too rich we waste gas and make less power, possably dilute the engine oil which can burn up the berrings. if it is just a drop in filter, i would not worry, but with any major change, its better to know before there is a problem

mbtoloczko · #15 10-05-2003, 12:05 PM

Quote:

Originally posted by AFBeefcake
I wired mine in to O2 #2 which is pin 6 white wire on the 22 pin connector on the ECU.

hope that helps you out.

Is O2 #2 on the driver side or passenger side? Do you know which ECU wire has the signal for O2 #1? Is there a pin out diagram for the ECU here on the network?